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Distribution of Nb atom in the TiAl+Nb system

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Rare metals 2001年第1期20卷 5-12页

作者： Xiaodong Ni, Xidong Hui, Guoliang Chen (Applied science School, university of science and technology beijing, beijing 100083, china state key laboratory for advanced metals and materials, university of science and technology beijing, china) Appl. Sci. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Based on MEAM (the modified embedded atom method) potential and an average atom model similar to B-W (Bragg-Williams) method, the distribution of Nb atoms in TiAl+Nb compounds with various composition was calculated. The calculation results showed that Nb atoms prefer to occupy the Ti sublattice of L10 structure for all compounds in question. With increasing atomic fraction of Nb and Al, Nb atoms exhibited a trend of ordered distribution on the Ti sublattice and result in a new L10 derivative superlattice structure.

关键词： Computer simulation Intermetallics Superlattices Ternary systems

Structure Evolution of Bulk Metallic Glass Zr_(52.5)Ni_(14.6)Al_10Cu_(17.9)Ti_5 during Annealing

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Journal of materials science & technology 2000年第4期16卷 357-361页

作者： Guo HE, Zan BIAN and Guoliang CHEN (state key laboratory of advanced metals and materials, university of science and technology beijing,beijing 100083, china) state key laboratory of advanced metals and materials University of Science and Technology Beijing Beijing 100083 China

Bulk metallic glass Zr_52.5Ni_14.6Al_10Cu_17.9Ti_5 was prepared by melt injection casting method. Its glass transition and crystallization temperatures were determined by differential scanning calorimetry (DSC) to be 631 K and 710 K respectively. By analysis of X-ray diffractometry (XRD) and transmission electron microscopy (TEM ), the predominant crystallized phase of Zr_2Ni0.67O0.33 distributed on glass state matrix was detected after annealing at 673 K for 600 s. The transformation to Zr_2Ni_0.67O_0.33 and a small amount of ZrAl and Zr_2Cu took place after annealing for 600 s at temperature from 703 K to 723 K. With increasing annealing temperature from 753 K to 823 K, the amounts of ZrAl and Zr_2Cu increased, but the size of the crystals did not significantly change. The transformation to Zr_2Ni_0.67O_0.33 is interface-controlled, but is diffusion-controlled to Zr_2Cu and ZrAl. With increasing annealing temperature up to 200 K above T_x, the nanometer grains became very fine because of the increase of nucleation rate for Zr_2Cu and ZrAl.

关键词： Structure Evolution of Bulk Metallic Glass Zr Ti5 during Annealing Al10Cu Ni Cu

Micro-alloying of yttrium in Zr-based bulk metallic glasses

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Progress in Natural science:materials International 2011年第1期21卷 46-52页

作者： Wei-jie PENG,Yong ZHANG state key laboratory for advanced metals and materials, university of science and technology beijing,beijing 100083.china state key laboratory for advanced metals and materials University of Science and Technology Beijing Beijing 100083 China

The effect of yttrium addition on the glass-forming ability(GFA) and mechanical properties of the Zr-based (Zr0.525Al0.1Ti0.05Cu0.179Ni0.146)100-xYxand(Zr0.55Al0.15Ni0.1Cu0.2)100-xYx(x=0,0.2,0.4 0.6,1,2) alloys was ***-alloying of 0.6%yttrium enhances the room temperature ductility as well as the GFA of the Zr-based *** mechanism of enhancing the GFA and room temperature ductility was *** is indicated that proper yttrium addition stabilizes the undercooled liquid by means of forming lots of ordered clusters,thus improving the GFA and the room temperature ductility.

关键词： micro-alloying glass-forming ability Zr-based alloys yttrium

MEAM Potential with Angular Dependence for TiAl

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Rare metals 2001年第1期20卷 13-17页

作者： Xiaodong Ni, Xitao Wang, Guoliang Chen (Physics Department, university of science and technology beijing, beijing 100083, china state key laboratory for advanced metals and materials, university of science and technology beijing, beijing 100083, china) 北京科技大学新金属材料国家重点实验室北京 100083 北京科技大学北京 100083

The modified embedded atom method (MEAM) is an empirical extension of the embedded atom method (EAM) that includes angular forces. By fitted to the lattice constants, the cohesive energy, the APE (anti-phase boundary) energy, and the vacancy formation energy of TiAl, an accurate MEAM potential is obtained for the TiAl system with L10 structure. The calculation results of the properties of TiAl are in good agreement with experiments and the results of first principle (F.P.) calculations.

关键词： embedded atom method TiAl alloy angular dependence potential intermetallics

Precipitation of α Phase in the Massive and Feathery Structures in TiAl Alloys during Aging in the Single α Field

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Journal of materials science & technology 1999年第5期15卷 469-472页

作者： Weijun ZHANG and Glloliang CHEN(state key laboratory for advanced metals and materials, university of science and technology beijing, beijing 100083, china To whom correspondence should be addressed ) state key laboratory for advanced metals and materials University of Science and Technology Beijing Beijing 100083 China

Precipitation of α-phase in massive and feathery microstructures was studied during aging in the single α field. It was found that the α-phase mainly precipitated along the γ-plate interfaces as laths in the feathery structure, while it nucleated at various sites in the massive structure in the form of particles and dominantly as plates. Precipitation of α-plates in the massive structure occurred by the difFusional ledge mechanism. The γm→α reaction proceeded by the growth of previously nucleated α-precipitates, and chiefly by the development of new α-plates

关键词： TiAl Precipitation of Field Phase in the Massive and Feathery Structures in TiAl Alloys during Aging in the Single

Giant Magnetostrictions of Tb-Dy-Fe Polycrystals with < 110 > Axial Alignment

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Journal of materials science & technology 2000年第2期16卷 175-176页

作者： Shouzeng ZHOU, Xuexu GAO, Maocai ZHANG, Qing ZHAO and Zhenhlla SHI (state key laboratory for advanced metals and materials, university of science and technology beijing, beijing 100083, china) state key laboratory for advanced metals and materials University of Science and Technology Beijing Beijing 100083 China

Preparing method and processing of Tb-Dy-Fe alloy samples with [110] axial orientation as well as their magnetostrictive properties have been studied. It has been found that the magnetostrictive strains of polycrystal samples with [110] axial orientation can reach (1550-1900) ×10~-6 in a low magnetic field less than 80 kA/m, which are equal to or somewhat better than that of the polycrystal samples with [112] axial orientation.

关键词： 110 Giant Magnetostrictions of Tb-Dy-Fe Polycrystals with Axial Alignment Fe Dy

Influence of Ru addition on microstructure and stress-rupture property of Ni-based single crystal superalloys

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Progress in Natural science:materials International 2010年第1期20卷 61-69页

作者： Jing-yang CHEN~1,Qiang FENG~(1,2),La-mei CAO~3,Zu-qing SUN~1 1.state key laboratory for advanced metals and materials,university of science and technology beijing, beijing 100083.china 2.National Center for materials Service Safety,university of science and technology beijing,beijing 100083.china 3.National key laboratory of science and technology on advanced High Temperature Structural materials, beijing Institute of Aeronautical materials,beijing 100095,china state key laboratory for advanced metals and materials University of Science and Technology Beijing Beijing 100083 China National Center for materials Service Safety University of Science and Technology Beijing Beijing 100083 China National key laboratory of science and technology on advanced High Temperature Structural materials Beijing Institute of Aeronautical Materials Beijing 100095 China

The effects of Ru on the microstructure and stress-rupture property were investigated in two experimental Ni-based single crystal superalloys with and without Ru addition(5.1%,mass fraction).The results indicate that the morphology ofγ' precipitates in the dendrite core and interdendritic region are intermediate and nearly spherical,respectively,in the Ru-free alloy after being aged at 1100℃for 8 *** Re partitioning ratio increases due to Ru addition and Ru partitioned preferentially to theγphase in both dendrite core and interdendritic region of the Ru-containing alloy,which results in more negative lattice misfit and more cuboidalγ' ***,theγ' volume fraction increases while the precipitate size and y channel width decreases due to Ru addition in both dendrite core and interdendritic *** addition improves the stress-rupture life at 1100℃/140 MPa significantly due to higherγ' volume fraction,more negative lattice misfit and a well rafting structure as well as lessγchannel width.

关键词： Ni-based superalloys ruthenium elemental partitioning ratio lattice misfit γ’ morphology stress-rupture property

Effect of additive elements on exchange coupling and spin reorientation transition of nanocrystalline single-phase Nd-Fe-B alloy

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science china(Technological sciences) 2010年第9期53卷 2323-2327页

作者： BAO XiaoQian,GAO XueXu,ZHU Jie & ZHOU ShouZeng state key laboratory for advanced metals and materials,university of science and technology beijing,beijing 100083.china state key laboratory for advanced metals and materials University of Science and Technology Beijing Beijing China

Nd12.3Fe81.7-xZrxB6.0 (x=0,1.5) and (NdDyTb)12.3(FeZrNbCu)81.7-yCoyB6.0 (y=0,12) ribbons were prepared by melt spinning at 22 m/s and subsequent *** influences of Zr,Dy/Tb and Co substitutions on magnetic properties and spin reorientation transitions of nanophase Nd2Fe14B have been systematically *** with Zr-free sample,the remanence,intrinsic coercivity and maximum energy product for Nd12.3Fe80.2Zr1.5B6.0 ribbon increase by 10.8 %,17.8 % and 60.2 %,*** significant improvement of magnetic properties originates from the finer grains of the sample by introducing Zr,which leads to the stronger exchange coupling between neighboring *** intrinsic coercivity for (DyTb)-substituted ribbon is significantly increased although the remanence is reduced,which could be compensated by the substitution of Co for *** spin reorientation temperature Tsr of nanocrystalline Nd2Fe14B alloys was determined by measuring the ac magnetic *** was found to be lower than that of bulk *** substitutions of Zr,Dy/Tb and Co result in reduction of *** smaller the grain size,the lower the Tsr will *** of spin reorientation on magnetization characteristics of nanophase Nd2Fe14B was discussed.

关键词： nanocrystalline Nd-Fe-B magnet exchange coupling spin reorientation transition magnetic properties

Influence of sample surface condition on nano indentation experiment

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Rare metals 2002年第2期21卷 131-132页

作者： WANG Yanli, LIN Zhi, LIN Junpin, PENG Jihua, and CHEN Guoliangstate key laboratory for advanced metals and materials, university of science and technology beijing, beijing 100083, china university of science and technology beijing State Key Laboratory for Advanced Metals and Materials 北京 100083

The microhardness and elastic modules of the materials weremeasured using the Nano Indenter II, which is a new measuring systemfor the mechanical properties of materials on nano-scale. It candetermine themicrohardness, elastic modules and other mechanicalproperties of materials through measuring applied load and depthunder indenter tip. The results indicated that surface condition ofsample such as the surface roughness affects the experimental preci-sion.

关键词： microhardness elastic modules Nano Indenter